The present invention relates to a robot hand changer, and more particularly to a robot hand changer for automatically attaching a hand for gripping a workpiece or effecting other operations, detachably to a robot, and for reliably and accurately mounting a hand to a robot even if the hand is relatively heavy, the device being capable of easily transmitting control signals and the like between the robot and the hand and being highly reliable in sufficiently withstanding frequent connection and disconnection between the robot and the hand.
In recent years, factories have seen widespread use of robots for automatically machining, conveying, and assembling workpieces to mass-produce products efficiently. The robots are generally designed to effect single operation. Since however many factories produce a wide variety of different products, there has been a demand for a multifunction robot which can perform different kinds of operation.
To meet such a demand, there has been proposed a robot hand changer for selectively attaching hands for machining, conveying, assembling workpieces detachably to a robot, so that the single robot can perform many types of operation with the use of desired hands.
A robot hand for gripping a passenger seat to install the same in an automobile body is relatively large and heavy. Since such a robot hand imposes a considerable load on a joint to a robot body, it is practically impossible to rely on a robot hand changer for use with the robot hand. Therefore, a robot hand changer has heretofore been employed to change relatively light hands, and hence a robot finds limited functions.
Lead wires, optical fibers, and pipes for supplying mediums to actuate a hand or a tool are exposed, and hence are susceptible to damage under external forces during operation of the robot.
The robot body and the hand are required to be not only mechanically coupled to each other, but also have an easily detachable construction which can supply electric power, transmit control signals, and deliver a hydraulic or pneumatic fluid for actuating the hand, between the robot body and the hand.
The control signals to be transmitted between the robot body and the hand is fed through many electric cables which are coupled by a connector. Where the hand is replaced with others at frequent intervals, the durability of the connector may be reduced by frequent connection and disconnection thereof. Recently, efforts have been made to eliminate the mechanical connection in signal transmission by employing a magnetic connector in place of the mechanical connector or an optical connector through which optical signals converted from electric signals are transmitted. In case magnetic sensors are used in the connector, they are subject to disturbance arising from an external magnetic field and take up a large space since as many magnetic sensors are disposed as the number of electric cables used. Where optical control signals are transmitted through a single optical fiber, parallel control signals corresponding to the electric cables are converted to serial signals for transmission and the serial signals which are received are converted back to parallel signals. Converters required for such parallel-to-serial and serial-to-parallel signal conversion make the entire system complex and costly.